Well, the rubber bands have been a fail and on reflection it was bound to happen. The issue is that when some weight is placed on the gears, the top of the band will bunch until the tension on the lower pulls it along.
I’ve decided to make a winch system based on gears. This is the first prototype of this system.
It’s working relatively well but does need me to hold the based of the camera tray to provide some resistance… again, hopeful with this new design.